From b5a2ecec1fcfcca62ba46002c38776b2adb2ff3b Mon Sep 17 00:00:00 2001
From: Amazing Coder <wcadaydayup@gmail.com>
Date: Sat, 24 Aug 2024 14:56:41 +0800
Subject: [PATCH 1/2] v1.0-Only single digit integers are allowed in the input

---
 interpreter.py | 90 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 interpreter.py

diff --git a/interpreter.py b/interpreter.py
new file mode 100644
index 0000000..c04b680
--- /dev/null
+++ b/interpreter.py
@@ -0,0 +1,90 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+@file: interpreter.py
+@author: amazing coder
+@date: 2024/8/24
+@desc: simple demo for python interpreter v1.0
+"""
+from unittest.mock import right
+
+INTEGER, PLUS, EOF = 'INTEGER', 'PLUS', 'EOF'
+
+class Token(object):
+    def __init__(self, type, value):
+        self.type = type
+        self.value = value
+
+    def __str__(self):
+        return 'Token({type}, {value})'.format(
+            type=self.type,
+            value=repr(self.value)
+        )
+
+    def __repr__(self):
+         return self.__str__()
+
+class Interpreter(object):
+
+    def __init__(self, text):
+        self.text = text
+        self.pos = 0
+        self.current_token = None
+
+
+    def error(self):
+        raise Exception('Error parsing input')
+
+    def get_next_token(self):
+        text = self.text
+
+        if self.pos > len(text) - 1:
+            return Token(EOF, None)
+
+        current_char = text[self.pos]
+        self.pos += 1
+
+        if current_char.isdigit():
+            return Token(INTEGER, int(current_char))
+        if current_char == '+':
+            return Token(PLUS, current_char)
+        self.error()
+
+    def eat(self, token_type):
+        if self.current_token.type == token_type:
+            self.current_token = self.get_next_token()
+        else:
+            self.error()
+
+    def expr(self):
+        self.current_token = self.get_next_token()
+        left = self.current_token
+        self.eat(INTEGER)
+
+        op = self.current_token
+        self.eat(PLUS)
+
+        right = self.current_token
+        self.eat(INTEGER)
+
+        result = left.value + right.value
+        return result
+
+def main():
+    while True:
+        try:
+            text = input('input a express like "1+2"(Only single digit integers are allowed in the input)> ')
+        except EOFError:
+            break
+
+        if not text:
+            continue
+
+        interpreter = Interpreter(text)
+        result = interpreter.expr()
+        print(result)
+
+if __name__ == '__main__':
+    main()
+

From bdc7239d0b9b46defa31628eb67f3b6def1a3f0c Mon Sep 17 00:00:00 2001
From: Amazing Coder <wcadaydayup@gmail.com>
Date: Sat, 24 Aug 2024 14:56:41 +0800
Subject: [PATCH 2/2] v1.0-Only single digit integers are allowed in the input

---
 interpreter.py | 1 -
 1 file changed, 1 deletion(-)

diff --git a/interpreter.py b/interpreter.py
index c04b680..66bf101 100644
--- a/interpreter.py
+++ b/interpreter.py
@@ -7,7 +7,6 @@
 @date: 2024/8/24
 @desc: simple demo for python interpreter v1.0
 """
-from unittest.mock import right
 
 INTEGER, PLUS, EOF = 'INTEGER', 'PLUS', 'EOF'